The invention relates to plumbing systems for transportation conveyances, including over-the-road vehicles, railway cars and recreational boats (e.g., yachts).
Over-the-road domestic vehicles, such as motor homes, travel trailers and the like, are typically equipped with a system of plumbing for distribution of water from an external source to different locations within the vehicle, e.g. kitchen, washroom, etc. The system of plumbing in more comfortable vehicles will often include a heater for delivery of hot water. In many instances, the plumbing system is adapted for connection to an external source of water supply under pressure, e.g., as available in most camping areas. The plumbing system will also generally include an auxiliary pump for generating pressure for delivery of water throughout the system in cases where the external source is not pressurized, e.g. water supplied from a tank, well or, more remotely, from a natural stream or pond. Since an over-the-road vehicle is often stored in an unheated area during the off season, the plumbing system most typically will include means for draining the pipes, as required in colder climates to avoid damage to the system, e.g. due to freezing. After the plumbing system is drained, a non-toxic anti-freeze may be added to the system for added protection against freezing.